Scientists are close to developing a blood test to detect Alzheimer's disease years before symptoms appear.
La Trobe University researchers have identified abnormalities in the blood linked to the degenerative condition, which affects more than 350,000 Australians.
Molecular biologist Lesley Cheng said detecting abnormalities with a simple blood test could provide doctors with the definitive diagnostic tool they currently lack. Early diagnosis would mean patients could receive treatment earlier, which could boost the chances of stalling the symptoms.
"At the end of the day, what we want is a strong biomarker that will differentiate between healthy patients and Alzheimer's patients," Dr Cheng said.
Led by Andrew Hill, the research team identified 16 abnormalities in the blood of Alzheimer's patients, after isolating a type of genetic material known as microRNA, which controls gene expression.
MicroRNA is found at concentrated levels in cell secretions, or exosomes, which can be isolated from blood. Examining the microRNA revealed there were differences between Alzheimer's patients' microRNA and that of healthy people.
Three of the 16 abnormalities identified in the blood target genes that are already associated with Alzheimer's.
"The idea is to screen people who aren't displaying symptoms," Dr Cheng said. "We can then identify their risk of developing Alzheimer's disease and intervene earlier."
Currently no single test exists to identify or diagnose Alzheimer's disease. Instead, the condition is diagnosed with neuro-psychological tests, including memory tests and word association. Doctors also rely on physical and neurological examinations and establishing whether there is a family history. However, some measures are problematic as they can be subjective.
A medical imaging scan looking for signs of brain matter degeneration can also be done, but degeneration is not limited to Alzheimer's.
The only way to know if a person has Alzheimer's for certain is after death, when brain tissue is analysed.
Dr Cheng said the technology used to develop the blood test also had the potential to diagnose other neurodegenerative diseases, such as Parkinson's disease.
According to the Australian Institute of Health and Welfare, more than 342,800 Australians or one in 10 over 65, live with dementia. Alzheimer's is the most common form, affecting around 70 per cent of people with dementia.
There is no cure for Alzheimer's disease, but in mild or moderate cases, cognitive function can be managed with medication.
Dr Cheng would like to recruit another 500 people for the next phase of the study by the CSIRO's AIBL research group. Healthy people or Alzheimer's patients interested in participating can register online or call 1800 443 253.
